1. Field of the Invention
The present invention relates to a method of producing a fiber-reinforced resin-molded member to be connected to a different resin-molded member, and a method of connecting members using fiber-reinforced resin-molded members produced by the same producing method.
2. Description of Related Art
Fiber-reinforced resin members (fiber-reinforced plastics (FRP)) formed of resin and reinforcing fiber materials contained in the resin (fiber-reinforcing materials) are used in various industrial fields, such as an automotive industry, a construction industry, and an aviation industry because of light weight and high strength thereof. For example, in the automotive industry, for the purpose of attaining reduction in weight of vehicles while ensuring strength of vehicles so as to manufacture environment-friendly vehicles with an enhanced fuel-efficiency, the aforementioned fiber-reinforced resin members are applied to non-structural members where designing properties are required. The non-structural members include frame structural members of vehicles such as front side members, center cross members, pillars, lockers, and floors of the bodies, and door outer panels and hoods.
As a method of connecting fiber-reinforced resin members to each other, there is commonly employed a connecting method through adhesive, or a connecting method using connecting components, such as bolting, screwing, and self-pierce riveting, or a combination of these methods.
There are a variety of methods of connecting fiber-reinforced resin members to each other, but the aforementioned conventional methods have various problems.
Specifically, there are the following problems: the method of using adhesive requires some time to bond the members; and the method through bolting, screwing, or self-pierce riveting requires connecting components, thus manufacturing time becomes increased, or manufacturing cost associated with the connecting components becomes increased.
Particularly, in the case of connecting fiber-reinforced resin members having three-dimensionally complicated shapes to each other using connecting components, such as bolts, it is not easy to handle alignment between the fiber-reinforced resin members to be connected; thus it is likely to increase assembly procedures to connect the members to each other using the connecting components. In connection through adhesive or welding, it is difficult to apply adhesive to, or apply heat to the entire portions (overlaid portions) to be connected that are three-dimensionally complicated as uniformly as possible.
Japanese Patent Application Publication No. 2002-11795 discloses a method of joining fiber-reinforced plastic members configured such that carbon fiber materials are protruded from respective FRP members at a joint target portion of the FRP members, the FRP members are disposed to be opposite to each other at the joint target portion, projecting ends of the fiber materials are laid over each other, and a resin material is supplied into a region where the carbon fiber materials are laid over at the joint target portion, and is then cured. Japanese Patent Application Publication No. 2011-79289 disposes a method of joining fiber-reinforced plastic members configured such that at least a partial matrix in a surface of a portion to be bonded to a synthetic resin of a fiber-reinforced plastic substrate is removed through physical or chemical means so as to expose reinforcing fibers to the surface, and a plasticized second polymer material is formed in a space where the matrix is removed so as to permeate voids and rough portions among the exposed reinforcing fibers with the plasticized second polymer material, and then cure this plasticized polymer material, thereby attaining firm adhesion through mechanical bonding.
These documents provide description regarding removal of the formed polymer material through chemical means or physical means as a method of protruding the carbon fiber materials from the respective FRP members. For example, if the matrix resin is a thermoplastic resin, it may be considered to employ a method of protruding the carbon fiber materials by dissolving the matrix resin using an appropriate solvent, or a method of melting the FRP member through heating to partially remove the FRP member so as to protrude the carbon fiber materials. Meanwhile, if the matrix resin is a thermosetting resin, it may be considered to employ a method of thermally decomposing the FRP member using a laser beam so as to protrude the carbon fiber materials.
Even if any of the above methods is applied, it is not easy to expose the fiber-reinforcing material from the surface of the member. For example, in the method of using the solvent, it is difficult to treat only a desired region of the member because liquid is used, and it is also necessary to consider a problem of treatment of the solvent as well as operational environments. In the method of exposing the fiber-reinforcing material through heating, there are problems that partial heating is difficult, and it is difficult to preferably separate only melted resin because the melted resin has a high viscosity. In the method of thermally decomposing the resin using a laser beam, there is a problem that facility cost becomes increased, and a location of a production site is limited.